List Group By 用法

var dealOtherDetail = items.GroupBy(x => new { x.DetailID }).Select(g => new { g.Key.DetailID, qty = g.Sum(a => a.AppointQty) }).ToList();

linq group by多个字段,返回多个字段

直接上例子.

var wflist = from u in db.TWelFare  
  where u.fy_no == fy_no  
  orderby u.we_no  
  group u by new { weno = u.we_no, wename = u.we_name } into g  
  select new { g.Key.weno, g.Key.wename };

GroupBy(x => new { x.genTime, x.joinCount }).Select(x => new { x.Key.genTime, Count = x.Count() })